Bitcoin, for now, is not suitable to become a national currency of any country. Bitcoin's value is too volatile so a product or service will always change in price with respect to the price of Bitcoin. Also, a transaction fee is there with every transaction, this is not practical in using in a daily basis. It will be hard for the government to control the scenario. So if a country will make Bitcoin as its national currency then they have to regulate it first.
Your facts are right, bitcoin is suitable global currency, you cannot make it as national currency, people from whole world know about bitcoin and they work at their homes to earn it. Bitcoin is not a small platform there is a large numbers of team members that regulate and continue its growth and flow in the market which can be very easy for a single country to perform.